冲击加载下的砂岩动态断裂全过程的实验和分析
发布时间：2019-01-05 10:21
【摘要】：采用圆孔内单边裂纹平台巴西圆盘(HSCFBD)新型试样在直径为100 mm的分离式霍普金森压杆上进行径向冲击加载,完成I型动态断裂实验,首次研究了砂岩的动态断裂全过程。实验表明,在低加载气压(0.16~0.17 MPa)驱动炮弹条件下,炮弹撞击速度为3.7~4.4 m/s,检测到试样的破裂历经裂纹的动态起裂、扩展和止裂3个阶段,止裂后到第2次起裂开始,裂纹停滞较长一段时间。采用裂纹扩展计测得裂纹起裂、扩展和止裂完整过程的瞬时时间,以此确定试样的动态起裂时刻、裂纹扩展速度和止裂时刻,并运用实验-数值-解析法分别得到砂岩的动态起裂韧度、扩展韧度和止裂韧度。从微观角度分析了动态起裂韧度和起裂时间的加载率效应。最后,初步讨论了试样内应力波反射对止裂的影响。
[Abstract]:In this paper, a new type of specimen of Brazilian disc (HSCFBD) with one-sided crack in the hole is subjected to radial impact loading on the split Hopkinson pressure bar with diameter of 100 mm. The mode I dynamic fracture experiment is completed, and the whole dynamic fracture process of sandstone is studied for the first time. The experimental results show that the impact velocity of the projectile is 3.74.4m / s under the condition of low loading pressure (0.16o0.17 MPa). It has been detected that the fracture of the specimen goes through three stages of dynamic crack initiation, propagation and stopping crack. From the end of the crack to the beginning of the second crack, the crack stagnates for a long time. The instantaneous time of the whole process of crack initiation, propagation and crack arrest is obtained by means of crack propagation measurement, so as to determine the dynamic initiation time, crack propagation speed and crack arrest time of the specimen. The dynamic fracture initiation toughness, extension toughness and crack stop toughness of sandstone were obtained by means of experimental-numerical-analytical method. The effect of loading rate on dynamic initiation toughness and crack initiation time is analyzed from the microcosmic point of view. Finally, the effect of stress wave reflection on crack arrest is discussed preliminarily.
【作者单位】： 四川大学建筑与环境学院;地质灾害防治与地质环境保护国家重点实验室;水力学及山区河流开发保护国家重点实验室;
【基金】：高等学校博士学科点专项科研基金资助项目(201301181130013)
【分类号】：TD315
，
本文编号：2401636
[Abstract]:In this paper, a new type of specimen of Brazilian disc (HSCFBD) with one-sided crack in the hole is subjected to radial impact loading on the split Hopkinson pressure bar with diameter of 100 mm. The mode I dynamic fracture experiment is completed, and the whole dynamic fracture process of sandstone is studied for the first time. The experimental results show that the impact velocity of the projectile is 3.74.4m / s under the condition of low loading pressure (0.16o0.17 MPa). It has been detected that the fracture of the specimen goes through three stages of dynamic crack initiation, propagation and stopping crack. From the end of the crack to the beginning of the second crack, the crack stagnates for a long time. The instantaneous time of the whole process of crack initiation, propagation and crack arrest is obtained by means of crack propagation measurement, so as to determine the dynamic initiation time, crack propagation speed and crack arrest time of the specimen. The dynamic fracture initiation toughness, extension toughness and crack stop toughness of sandstone were obtained by means of experimental-numerical-analytical method. The effect of loading rate on dynamic initiation toughness and crack initiation time is analyzed from the microcosmic point of view. Finally, the effect of stress wave reflection on crack arrest is discussed preliminarily.
【作者单位】： 四川大学建筑与环境学院;地质灾害防治与地质环境保护国家重点实验室;水力学及山区河流开发保护国家重点实验室;
【基金】：高等学校博士学科点专项科研基金资助项目(201301181130013)
【分类号】：TD315
，
本文编号：2401636
本文链接：https://www.wllwen.com/kejilunwen/kuangye/2401636.html
